Excerpts from Sean Leather's message of Wed Nov 11 21:24:43 +0100 2009:
Is there a name for the following concept? Can you point me to any references on it?
Suppose I have the following two functions ...
swap1 :: (Int, Char) -> (Char, Int) swap2 :: (Char, Int) -> (Int, Char)
... and, for some reason, I think I can unify these into a single function. I think, hmm, given that the structure is that same, let's do a first pass:
swap? :: (a, b) -> (c, d)
But then I go back to the input types to confirm that this will work, and, alas, it will not, because there are similarities that I missed. This is way too general. I need to ensure that what's an Int stays an Int and likewise for Char.
swap! :: (a, b) -> (b, a)
In the literature this is also called anti-unification (anti-unifier). These techniques had been used for formalising some overloading systems. -- Nicolas Pouillard http://nicolaspouillard.fr